A new review has assembled all the available studies on supplements for elite soccer players, concluding the data best supports the use of caffeine and creatine to improve performance.

Hank Schultz, Senior Editor

July 19, 2023

3 Min Read

The new research was published this week in the Journal of the International Society of Sports Nutrition. It was the work of a team of researchers associated with the Portuguese Football Federation and the University of Porto. 

Trying to answer question of what really works 

Sports nutrition studies can be hard to interpret. Hundreds of studies are published each year, but many are small in scale and short in duration. And the study populations and the protocols and interventions used can be highly variable.  

Elite athletes involved in ongoing training and competition have limited time to participate in studies, meaning results from research done with lesser trained athletes usually must be extrapolated. Will an ingredient that helps a casually trained individual really move the needle for an athlete who is already near the peak of his or her potential? 

To try to answer that question specifically for soccer players, the Portuguese team devised a study filter that sought out studies done only with elite players, both men and women. 

The research team found more than 1,043 records to consider. After applying their filters, which included along with player levels that the studies must be in English and must have placebo controls, they were left with 113 studies for further review. 

Related:Is it time to reconsider creatine dosing?

They ended up with 18 studies to be included in the final review, which covered 307 elite players (244 men and 63 women). 

In addition to caffeine and creatine, the researchers evaluated studies that used beetroot juice, tart cherry juice, carbohydrate/electrolyte sports drinks, protein, sodium bicarbonate with minerals, yohimbine and a proprietary nutraceutical formula. 

Caffeine, creatine had most data 

Caffeine in various delivery forms was the most studied ingredient. Studies used caffeinated beverages, capsules and caffeinated chewing gum. 

Among the effects observed were higher average top speeds in a repeated sprint test, better performance on a jump test and more distance covered at speeds ranging from a brisk run to sprinting in real and simulated matches.   

The latter measure was particularly striking as two of the caffeine studies found the caffeine groups significantly outran their control peers. In the study using GPS measures from an actual match, the players using caffeine performed on the average 30 sprints vs. 24 in the control group. In the study using a simulated match protocol, which was of shorter duration than an actual match, the figures were 21 (caffeine group) and 16 (control group). 

The creatine studies found a benefit in anerobic measures, improving short-distance sprint times. The studies also found a benefit of preserving sprint times after repeated sprints, with the placebo group slowing down more than the creatine-supplemented players. 

Other ingredients showed promise, but had less data 

The other ingredients were represented only by single studies in the review; thus, the benefits were less supported by overall data, the researchers said.  

The protein studies predominantly showed benefits in helping players maintain performance in the face of fatigue. The supplemented players neither ran faster nor jumped higher than their peers. 

The beetroot juice study and tart cherries studies followed in that vein, with the supplementation interventions working to prevent erosion of performance in the face of fatigue, rather than providing an absolute boost. 

The sodium bicarbonate study did find a reduction in total time over an anaerobic sprint test, which is similar to findings using this intervention in other sports. The challenge with this intervention has always been finding a way to ingest a high enough dosage without inducing unacceptable gastrointestinal issues

The yohimbine study and the study using a proprietary nutraceutical formula (branded as Resurgex plus) found no benefits over placebo. 

“The results of this systematic review may contribute to increasing confidence in using dietary supplements such as creatine monohydrate, protein, and caffeine. Nitrate and tart cherry supplementation, typically available in the form of drinkable concentrates, should be evaluated mindfully, as its efficacy depends on several factors,” the researchers concluded. 


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About the Author(s)

Hank Schultz

Senior Editor, Informa

Hank Schultz has been the senior editor of Natural Products Insider since early 2023. He can be reached at [email protected]

Prior to joining the Informa team, he was an editor at NutraIngredients-USA, a William Reed Business Media publication.

His approach to industry journalism was formed via a long career in the daily newspaper field. After graduating from the University of Wisconsin with degrees in journalism and German, Hank was an editor at the Tempe Daily News in Arizona. He followed that with a long stint working at the Rocky Mountain News, a now defunct daily newspaper in Denver, where he rose to be one of the city editors. The newspaper won two Pulitzer Prizes during his time there.

The changing landscape of the newspaper industry led him to explore other career paths. He began his career in the natural products industry more than a decade ago at New Hope Natural Media, which was then part of Penton and now is an Informa brand. Hank formed friendships and partnerships within the industry that still inform his work to this day, which helps him to bring an insider’s perspective, tempered with an objective journalist’s sensibility, to his in-depth reporting.

Harkening back to his newspaper days, Hank considers the readers to be the primary stakeholders whose needs must be met. Report the news quickly, comprehensively and above all, fairly, and readership and sponsorships will follow.

In 2015, Hank was recognized by the American Herbal Products Association with a Special Award for Journalistic Excellence.

When he’s not reporting on the supplement industry, Hank enjoys many outside pursuits. Those include long distance bicycle touring, mountain climbing, sailing, kayaking and fishing. Less strenuous pastimes include travel, reading (novels and nonfiction), studying German, noodling on a harmonica, sketching and a daily dose of word puzzles in The New York Times.

Last but far from least, Hank is a lifelong fan and part owner of the Green Bay Packers.

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